Method of and apparatus for controlling steam engines



Dec. 14 1926. 1,610,528

R. F. METCALFE METHOD OF' AND APPARATUS FOR CONTROLLING STEAM ENGINES @Y#ZM Dec. 14 1926.

R. F. METCALFE METHOD OF ANI? APPARATUS FOR CONTROLLING STEAM ENGINESFiled Dec. 4, 1919 3 Sheets-Sheet 2 'i Milli! i 1,610,528 R. F. METCALFEMETHOD 0E AND APPARATUS Foa CONTEOLLING STEAM ENGINES Filed Dec. 4, 19195 Sheets-Sheet ."5

6()a is carried by the pin 60 and with the cam 54 in neutral positionthe roller 60t is located in a socket h, the sides of this socket makinga quick-acting cam for swinging the rock arm 63 with the swingingmovement of the cam 54. The surfaces 6l and 62 at each side of thesocket 60b are arcs of a circle about the center of the shaft 57 andconsequently simply provide a rolling surface for the roller GOn andconsequently lock the rock levers 63 in a given position after the camsat the sides of the sock-et 50h have moved it. The spring` 59 holds therock lever 63 in a position following the surfaces 6l and 62 and compelsa movement of the rock lever fol' lowing' the cams at the sides of thesocket G01 so that the rock lever will drop into the socket when the cam54 is brought to neutral. A. rock arm 65 is mounted on the shaft 64 andconnected by a bracket 67 with a cylinder 68. A plunger 59 is mounted inthe cylinder 63. A spring P.FO-operates against one head of the cylinderand against the plunger 69, the piston being provided with a spiufnpvseat 72. The rod is sereiv-threaded and extends into a screiv-threadedopening- 73 in the piston and is locked by a jam nut 74. A shoulder 76limits the movement ot the piston in the cylinder G3. A controllinglever 73 is fixed with the cam 5e and provided \vith a handle 77. Thislever operates over a segment 79. As shown the segment is scaled and thelever has an indicating` point 80. The neutral point on the segment isindicated at N. rlhe'point A indicates a movement of the cam to ,swingthe rock lever 63 out of the notch @0b. M indicates the maximum forwardposition of the controlling lever. Moving the controlling lever to Rmoves the cam surface 55 into position on the roller 52 and also throwsthe rock lever 63 in a reverse direction so as to throw the cut-olf. Forreverse control the throttle is actuated rather than the cutptiA1 andthis is accomplished through 'the cam surface 55 which is so graduatedas to give a ready control of the throttle.

Steam is supplied to the throttle valve from a source of supply throughthe pipe 32 and is delivered to the engine through a pipe 83.

The operation of the device is as follows: Vhen the operating lever Z7is thrown to the position A (see Fig. e) the rock lever 63 is rocked.This rocking of the lever 63 acting through the rock arm 65 moves thecylinder 68 toward the right. At this moment the engine is, of course.stationary and any liquid there may be in the cylinder 28 is forcedthrough the pipe 30 by Way of the opening 40 in the bypass valve and byWay of the pipe 38a, pipe 85 to the discharge Se leading to the tank 37.Consequently the movement ofthe cylinder 68 is accompanied by anapproximately equal movement, either immediate or immediately following,of the rod T5 and with it the rock arms nl and 19 and the link l0 isthus depressed throwing the link to a late cut-olf ahead. lllith theparts at this position the cam at the beginning of the surface 5Greaches the roller o2 and begins to open the throct its the throttle isopened and the engine started the pump 33 is started and begins to forceliquid through the pipes 32 into the cylinder 28. At the same time someliquid is forced through the bypass opening 4Q. its the engine speeds upthe resistance to the flow of liquid through the metered opening 4.0increases and this resistance builds up results in pressure on theliquid which pressure is communicated to the piston 27, thus .moving`the piston 2 toufard the left against the resistance of the spring` YO.rhis n ovement toward the left of the piston 17 is accompanied by amovement of the roel; arms 2l and i9 and consetpientlv of the link l0 soas to gradually shorten the cut-ott.

lnasmucli as the resistance to the tloiv of liquid varies very greatlyuf'ith its velocit* through a restriction. such as the meteredL opening'et), the cut-oitl is very quickly brought to a position which Will`.Qive an en `.eine speed which may for convenience be designated aminimum pre-determined speed. rThe throttle in the meantime iscoinpletely open so that a further movement of the throttle has noeffect in increasing or decreasing'the flow of steam. The continuedmovement, however, of the throttle tl'irough the action of the cam 5Gacts through the rod 43 upon the disc ll-l and opens the bypass valve,thus increasing the area of restriction at this bypass and consequentlydecreasingthe resistance to the itloiv of liquid. lllith this decreasein resistance there is a consequent decrease in pressure 1which resultsin a preponderance of force by the sprini` 70 as to effect a movement ofthe rod .75 toward the right and with it through the linka liereinbeforedescribed to the link l() to increase the cut-oil?. lt Will be seen,therefore. that by setting` the bypass valve at an;r position theresistance through the restriction is so measured with relation to thesneed as to eniect a very close response in the speed. of the engine.This is due to the fact that any change in velocity through thisrestriction varies the resistance as the square of the velocity.Consequently a very slight change in the velocity, this change beine;brought about by a change in the speed of the engine, makes such avariation the resistance and consequently in the pressure f the liquidas to varv the cut-ot`1 to a point which will maintain the engineapproriiiiately at the desired speed.

ln the normal running of the engine it is desirable to compel theoperator to control the speed by the cut-ott and this mechanism liliaccomplishes thi'spurpose but `withfthe reverse this islnot'necessary.Tore'versc the engi'n'e,'there`tore, the calm 54 is swung as the leverZS'is moved downwardly s'oas to 'swing the rock lever {S3-and with itthe roel; lever 65 to carry the rod 75 to thel'e'tt. vThis carries thelink l0 immediately to reverse position andthe control ot the engineisthus ellected lby, aithrottlingaction on` the cam 55, the cam55`be'ing shaped to, eilect this result.

Should the enginefbe 4driven by `rthe vehicle as in coasting downgradethe bypass valve will not entirely relieve the pump and I,'theret`ore;provide a relief v'alve'S'T. This isgconnecte'd with `the connection 8lby a pipeo and with the overtlowh by a pipe 31a. It. isprovided with avalve disc SS from wliichfextends a 'stem v89K. ,Aspring 90 operateslagainst the stem and' 'thef torce ofthe 'springmay be adjusted bythe'screw 91. .The screwy 9llis carried bythetrameftl?, extending from thevalve. VIntliisfway 1the valve may be loaded to anypressure desired,

What I claim as new is l. The method ot controlling steam enginesfwhichconsists in initially directly controlling'the cLit-ott,tliencontrolling the cutoil through a motor actuated by pressure rcn sponsiveto the speed ot the engine; and varying the pressure incident to a givenspeed ot the engine to adjust the speed ot the en? gine through thecut-oli".

2. The method of controlling steam engines; which consists in manuallyinitially throwing a variable cut-off to late cut-oli; driving a liquidat a speed varying with the speed ot the engine; regulating the cut-oli"with the liquid pressure; and bypassing and restricting` the liquid tocontrol its pressure.

8. The method otl controlling steam engines; which consists in manuallyinitially throwing a variable cut-oli to late cutoff; driving a liquidat a speed varying` with the speed ot the engine; regulating the cut-olfwith the liquid pressure; bypass and restricting the liquid to controlits pressure; and varying the amount ot restriction to vary theregulation.

4e. The method ot controlling steam engines; which consists in manuallythrowing a variable cut-oli. valve gear to late cut-ott as the enginethrottle is opened; driving a liquid at a speed varying as the speed ofthe engine varies; regulating the cut-ott of the engine with the liquidpressure; and bypassing and restricting the liquid to control thepressure.

5. The method ot controlling steam engines., which consists in manuallythrowingl a variable cut-ott valve gear to late cut-cti as the enginethrottle is opened; driving a liquid at a speed varying as the speed otthe engine varies; regulating the cut-ott ot the engine with the liquidpressure; bypassing and restricting the liquid to control the pressureand varying the v*amount lot 'restriction to vary 1the regulation.

VGIThe method of controlling steam cngines which 'consists in initiallydirectly controlling the cut-olii., then controlling the cut-olithrougl'i a motor actuated .by sure responsive to the speed ot the c e;driving a confined liquid at a speed varxfl ing asthe 'speed ot theengine, regulating the 'cut-'oli ot the engine with 'the liquidpressure', bypassing and restricting the liquid'to control its pressure;and varying the restriction to vary'tlie regulation.

7. 'In-a steam engine control, the combination ot' a variable cut-Voti3valve gear; a liquid pump driven by the engine; a manually actuatedcontrolling device; a yielding ccnnection'b'etween the valve gear andthev device;afmotoractuatedby the liquid pumped; andfmeans' forcommunicating the movement pres- .or thegniotorrto 'the valve Vgearagainst the resi'stance ot the connection.

8. In a steam engine coinrol, the combina tion @invariable 'cut-olivalve gear; a liquid pump-driven by; theengine; a manuallyactuated"controlling device; a yielding connection between the valvegear and the device; a motor actuated by the liquid pumped; and meansfor communicating the movement ot the motor to the valve gear againstthe resistance of the connection whereby the device may throw the valveto late cut-oli and the motor reduce the cut-off as the speed increases.

9. In a steam engine control, the combination ot a variable cut-oil1valve gear; a throttle; a manually actuated controlling device actuatingthe throttle; a yielding Connection between the device and the valvegear; the device and connection operating to initially open the throttleand to set the valve gear at late cut-ott; a motor acting against there` sistance ot' said connection to actuate the valve gear; and a liquidpump driven by the engine and actuating the motor, said pump varying thepressure with the speed ot the engine.

10. In a steam engine control, the combination of a variable cut-olfvalve gear; a throttle; a manually actuated controlling device actuatingthe throttle; a yielding connection between the device and the valvegear, the device and connection operating to initially open the throttleand to set the valve gear at late cut-oit; a motor acting against theresistance of said connection to actuate the valve gear; a liquid pumpdriven by the' IUS lll)

liti

to initially open the throttle and to set the valve gear at latecut-off; a motor acting against the resistance of said connection toactuate the valve gear; a liquid pump, driven by the engine andactuating the motor; a restricted bypass tor the liquid puinped; andIneans for varying the restriction ot the by pass as the throttle isopened.

12. ln a steain engine control, the combination ot a. variable cut-ott"valve gear; a throttle; a manually actuated controlling device actuatingthe throttle; a yielding connection between the device and the valvegear; the devices and connection operating to initially open thethrottle and to set the valve gear at late cut-0H; a inotor actingagainst the resistance of said connection to actuate the. valve gear; aliquid pump driven by the engine and actuating the inotor; a restrictedbypass tor the liquid pumped; and means for varying the restriction assaid device is actuated after the opening ot the throttle.

13. ln a steam engine control, the combination of a variable cut-olifvalve gear; a throttle; a controlling cain having a cam surface ioractuating the throttle and a cam surface for actuating the valve gear; ayielding connection between the cain and valve gear, the devices andconnection operating to initially open the throttle and to set the valvegear at late cut-off; a liquid actuated inotor operating against saidresista-nce; and a pu-nip actuated by the engine and delivering liquidunder pressure to said motor.

let. In a steain engine control, the coinbination ot a variable cut-ottvalve gear; a throttle; al controlling cain having a cani surface toractuating the throttle and a cam surface tor actuating the valve gear;a' yielding connection between the cani and valve.

gear, the devices and connection operating to initially open thethrottle and to set the valve gear at late cut-oit; a liquid actuatedmotor operating against said resistance; a puinp actuated by the engineand delivering liquid under pressure to said inotor; a bypassrestriction; a valve in said restriction; and a device carried with thethrottle for actuating said valve.

n testimony whereof l have hereunto set my hand.

ROBERT F. METCALFE.

